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Spring Boot – how to configure port

Posted by: admin November 2, 2017 Leave a comment

Questions:

Looking for way how to configure port in Spring boot app:

@Controller
@EnableAutoConfiguration
public class SampleController {

    @RequestMapping("/")
    @ResponseBody
    String home() {
        return "Hello World!";
    }

    public static void main(String[] args) throws Exception {
        SpringApplication.run(SampleController.class, args);
    }
}

That is all sources 🙂

Answers:

As said in docs http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#howto-change-the-http-port

either set server.port as system property using command line option to jvm --server.port=8090 or add application.properties in /src/main/resources/ with

server.port = 8090

For random port use

server.port=0

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There are two main ways to change the port in the Embedded Tomcat in a Spring Boot Application.

Modify application.properties

First you can try the application.properties file in the /resources folder:

application.properties file

Modify a VM option

The second way, if you want to avoid modifying any files and checking in something that you only need on your local, you can use a vm arg:

Go to Run -> Edit Configurations -> VM options

-Dserver.port=8090

Change port with a vm arg

Additionally, if you need more information you can view the following blog post here: Changing the port on a Spring Boot Application

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also, you can configure port programmatically

@Configuration
public class ServletConfig {
    @Bean
    public EmbeddedServletContainerCustomizer containerCustomizer() {
        return (container -> {
            container.setPort(8012);
        });
    }
}

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You can set port in java code:

HashMap<String, Object> props = new HashMap<>();
props.put("server.port", 9999);

new SpringApplicationBuilder()
    .sources(SampleController.class)                
    .properties(props)
    .run(args);

Or in application.yml:

server:
    port: 9999

Or in application.properties:

server.port=9999

Or as a command line parameter:

-Dserver.port=9999

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In case you are using application.yml add the Following lines to it

server:
     port: 9000

and of course 0 for random port.

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As explained in Spring documentation, there are several ways to do that:

Either you set the port in the command line (for example 8888)

-Dserver.port=8888 or --server.port=8888
-Dport=8888 or --port=8888

Example : java -jar -Dport=8888 test.jar

Or you set the port in the application.properties

server.port=${port:4588}

or (in application.yml with yaml syntax)

server:
   port: ${port:4588}

If the port passed by -Dport (or -Dserver.port) is set in command line then this port will be taken into account. If not, then the port will be 4588 by default.

If you want to enforce the port in properties file whatever the environment variable, you just have to write:

server.port=8888

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Since Spring Boot provides various configuration externalization mechanism (through various PropertySource implementations and/or processors wired into Environment object in order), you can set any property outside of your jar archive through following methods:

  1. Pass property through command line argument

    java -jar <path/to/my/jar> --server.port=7788
    
  2. From propety in SPRING_APPLICATION_JSON (Spring Boot 1.3.0+)

    • Define environment variable in U*IX shell:

      SPRING_APPLICATION_JSON='{"server.port":7788}' java -jar <path/to/my/jar>
      
    • By using Java system property:

      java -Dspring.application.json='{"server.port":7788}' -jar <path/to/my/jar>
      
    • Pass through command line argument:

      java -jar <path/to/my/jar> --spring.application.json='{"server.port":7788}'
      
  3. Define system property

    java -Dserver.port=7788 -jar <path/to/my/jar>
    
  4. Define OS environment variable

    • U*IX Shell

      SERVER_PORT=7788 java -jar <path/to/my/jar>
      
    • Windows

      SET SERVER_PORT=7788
      java -jar <path/to/my/jar>
      
  5. Place property in ./config/application.properties

    server.port=7788
    

    and run:

     java -jar <path/to/my/jar>
    
  6. Place property in ./config/application.yaml

    server:
        port: 7788
    

    and run:

     java -jar <path/to/my/jar>
    
  7. Place property in ./application.properties

    server.port=7788
    

    and run:

     java -jar <path/to/my/jar>
    
  8. Place property in ./application.yaml

    server:
        port: 7788
    

    and run:

     java -jar <path/to/my/jar>
    

You can combine above methods all together, and the former configuration in the list take precedence over the latter one.

For example:

SERVER_PORT=2266 java -Dserver.port=5566 -jar <path/to/my/jar> --server.port=7788

The server will start and listen on port 7788.

This is very useful providing default properties in PropertySources with lower precedence (and usually packaged in the archive or coded in the source), and then override it in the runtime environment. And it is the design philosophy of Spring Boot:

Be opinionated out of the box, but get out of the way quickly as requirements start to diverge from the defaults.


SERVER_NAME to sever.name conversion was done by Realxed Binding.

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If you would like to do it at running it locally than use this –

mvn spring-boot:run -Drun.jvmArguments='-Dserver.port=8085'

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You can specify port by overriding EmbeddedServletContainerFactory bean within your configuration (java based or xml). There you can specify port for used embedded servlet container. Please, see Spring Boot – Core “Embedded Servlet Container Support” paragraph and example there. Hope this helps.

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When you need a programatically way of doing it, you can set it during startup:

System.getProperties().put( "server.port", 80 );
SpringApplication.run(App.class, args);

This might help for things like environment dependent port.
Have a nice day

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In application.properties file present in resources:

server.port=8082

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To extend other answers:

There is a section in the docs for testing which explains how to configure the port on integration tests:


At integration tests, the port configuration is made using the annotation @SpringBootTest and the webEnvironment values.


Random port:

@SpringBootTest(webEnvironment=WebEnvironment.RANDOM_PORT)

You can inject the value using @LocalServerPort which is the same as @Value("${local.server.port}").

  • Example:

Random port test configuration:

@RunWith(SpringRunner.class
@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
public class ExampleTest {
   ...
   @LocalServerPort //to inject port value
   int port;
}

Defined port:

@SpringBootTest(webEnvironment=WebEnvironment.DEFINED_PORT)

It takes the value from server.port if is defined.

  • If is defined using @TestPropertySource(properties = "server.port=9192"), it overrides other defined values.
  • If not, it takes the value from src/test/resources/application.properties (if exists).
  • And finally, if it is not defined it starts with the default 8080.

Example:

Defined port test configuration:

@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.DEFINED_PORT)
@TestPropertySource(properties = "server.port=9192")
public class DemoApplicationTests {

    @Test
    public void contextLoads() {
    }

}

Questions:
Answers:
  1. As everyone said, you can specify in application.properties
    server.port = 9000 (could be any other value)

  2. If you are using spring actuator in your project, by default it points to
    8080, and if you want to change it, then in application.properties mention

    management.port = 9001 (could be any other value)

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Indeed, the easiest way is to set the server.port property.

If you are using STS as IDE, from version 3.6.7 you actually have Spring Properties Editor for opening the properties file.

This editor provides autocomplete for all Spring Boot properties. If you write port and hit CTRL + SPACE, server.port will be the first option.

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You can configure port in application.properties file
server.port=8090

OR

during runtime you can use command line arg
-Dserver.port=8090

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1.1 Update via a properties file.

/src/main/resources/application.properties

server.port=8888

Update via a yaml file.

   server:

     port: 8888

EmbeddedServletContainerCustomizer

@Component
public class CustomContainer implements EmbeddedServletContainerCustomizer {

    @Override
    public void customize(ConfigurableEmbeddedServletContainer container) {

        container.setPort(8888);

    }

}

Questions:
Answers:

You can add the port in below methods.

  1. Run -> Configurations section

  2. In application.xml add server.port=XXXX

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You can set that in application.properties under /src/main/resources/

server.port = 8090

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Add this in your application.properties file

server.port 8080

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Include below property in application.properties

server.port=8080

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Just have a application.properties in src/main/resources of the project and give there

server.port=****

where **** refers to the port number.

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When spring boot application starts, the embedded server such as Tomcat starts with a default port. The embedded tomcat starts with 8080 port as default. There are many ways to change default server port.

Using Property File (.properties/.yml)

To change server port using property file, we need to configure server.port property.

a. Using application.properties in classpath such as
src\main\resources\application.properties

server.port = 8585

The server will start with 8585 port. To get random server port, assign 0 to the property.

server.port = 0

Now spring boot will start the server on a port that is not being used currently by any server in the system.

b. Using application.yml in classpath such as
src\main\resources\application.yml.

server:
  port: 8585 

Server will start with 8585 port.

For random port, assign 0.

server:
  port: 0 

Using java Command with –server.port or -Dserver.port

Suppose we have an executable JAR named as my-app.jar, then while starting spring boot application using java command we can use the argument as follows.

Using –server.port

java -jar my-app.jar  --server.port=8585

Using -Dserver.port

java -jar -Dserver.port=8585 my-app.jar

Server will start with 8585 port.

Using java Command with –port or -Dport in Short

To make –server.port and -Dserver.port in short, we can remove server keyword and make it any short keyword such as –port and -Dport. We can use any short keyword. Here we are using port as short keyword. To achieve it we need to configure placeholder in property file as follows.

Using application.properties

server.port=${port:8282}

Using application.yml

server:
   port: ${port:8282}

If we do not pass the port as the argument then by default server will start with 8282. If we want a different port, then we need to pass desired port in argument as follows. Suppose we have an executable JAR named as my-app.jar.

Using –port

java -jar my-app.jar --port=8585 

Using -Dport

java -jar -Dport=8585 my-app.jar 

Server will start with 8585 port.

Using SERVER_PORT with SpringApplication Programmatically

SpringApplication has a method as setDefaultProperties() that is used to change spring boot default properties. Suppose we want to change default port then we need to create a Map and put a port with SERVER_PORT key. Find the example.

MyApplication.java

package com.humoyun;

import java.util.HashMap;
import java.util.Map;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class MyApplication {
    public static void main(String[] args) {
        SpringApplication application = new SpringApplication(MyApplication.class);
        Map<String, Object> map = new HashMap<>();
        map.put("SERVER_PORT", "8585");
        application.setDefaultProperties(map);
        application.run(args);
        }     
} 

Spring boot will start the server with 8585 port.

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You can also use SERVER_PORT environment variable to configure Spring Boot port. Just set the environment variable and restart the app:

set SERVER_PORT=9999 // on windows machine
export SERVER_PORT=9999 // on linux

Please note that if you do not set those environment variables system wide, you should run the boot app on the same session.

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The default port is : 8080 but we can customize the port number in application.properties
as shown below

spring.mvc.view.prefix=/WEB-INF/jsp/
spring.mvc.view.suffix=.jsp
server.port = 5050 -- #here we can give any port number.

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Mostly springboot runs on port:8080 because of embedded Tomcat. In some it may throw an error port 8080 already in use. To avoid this kind of issues we can config the server port.

Using application.properties

add server.port=9898

On runtime config

run your application with below arguments.

spring-boot:run -Drun.jvmArguments='-Dserver.port=8081'

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Using property server.port=8080 for instance like mentioned in other answers is definitely a way to go. Just wanted to mention that you could also expose an environment property:

SERVER_PORT=8080

Since spring boot is able to replace “.” for “_” and lower to UPPER case for environment variables in recent versions.
This is specially useful in containers where all you gotta do is define that environment variable without adding/editing application.properties or passing system properties through command line (i.e -Dserver.port=$PORT)

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You can configure your port in application.properties file in the resources folder of your spring boot project.
server.port=”port which you need”

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There are three ways to do it

1 Set server.port property in application.properties file

server.port = 8090

2 Set server port property in application.yml

server:
port: 8090

3 Set the property as system property in main method

System.setProperty(“server.port”,”8090″);

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In my case adding statement

server.port=${port:8081}

override the default tomcat server port.

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server.port=8080” will only works if your running application as a jar through main method,

This configuration will not work if your running this application as a war file through tomcat container.